Piston assembly transportation and installation apparatus and methods of transporting and installing a piston assembly therewith

ABSTRACT

A piston assembly transportation and assembly apparatus and methods of transporting and installing a piston assembly therewith are provided. The apparatus maintains a piston assembly in its assembled state during transportation without allowing damage and contamination to the piston assembly. The apparatus also facilitates storage and installation of the piston assembly into a cylinder bore. The apparatus includes a housing having a bore bounded by an inner cylindrical surface extending from a first end of the housing toward a second end of the housing. A chamfered surface diverges radially outwardly from the first end to mate with an upper surface of a stuffing cone during assembly. The second end has a wall extending radially inwardly from the inner cylindrical surface to axially confront an upper crown of the piston assembly to both prevent the piston assembly from passing though the apparatus and to prevent contamination from entering the apparatus.

This divisional application claims priority to U.S. application Ser. No.12/849,097, filed Aug. 3, 2010, and is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to internal combustion engine pistons,and more particularly to apparatus for transporting and installingpiston assemblies.

2. Related Art

The transportation of a piston assembly, including a piston head withone or more piston rings and a connecting rod, comes with knownproblems. For example, maintaining the ring or rings within theirrespective grooves during transportation can be problematic, therebyresulting in lost or damaged piston rings. Thus, in an effort to preventlosing or damaging piston rings and their associated ring grooves, thepiston rings can be maintained radially compressed in the ring grooves.However, a known problem of over compressing the piston rings results ifthe radial compression is too great. If the piston rings are overlycompressed in the ring grooves, the “free gap” desired and providedbetween ends of the piston ring is plastically reduced, which in turndetracts from the ability of the piston ring to provide the desiredexpanded radial compression against a cylinder wall in use. As such, thesealing and scraping function of the piston ring is diminished.

Further, assembling the piston assembly into a cylinder bore of anengine block is a complex process requiring the piston rings to be atleast slightly compressed radially for receipt in the cylinder bore. Itis known to use a compression sleeve, also referred to as stuffing coneor ring, during assembly that gradually causes the piston rings to becompressed radially inwardly along a constant tapered surfacesufficiently for receipt within the cylinder bore of the engine block.Although the compression sleeve functions well to aid in assembly, theaforementioned problems remain with respect to transporting and storingpiston assemblies prior to installation into an engine.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, a piston assemblytransportation and assembly apparatus configured to maintain a pistonassembly in its assembled state during transportation and to aid in theinstallation of the piston assembly into a cylinder bore is provided.The piston assembly transportation and assembly apparatus includes ahousing having a bore bounded by an inner cylindrical surface extendingfrom a first end of the housing toward a second end of the housing. Achamfered surface diverges radially outwardly from the first end towardthe second end and the second end has a wall extending radially inwardlyfrom the inner cylindrical surface to axially confront an upper crown ofthe piston assembly.

In accordance with another aspect of the invention, a piston assemblytransportation and assembly apparatus configured to maintain a pistonassembly in its assembled state during transportation and to aid in theinstallation of the piston assembly into a cylinder bore in combinationwith a stuffing cone is provided. The stuffing cone has a through boreextending between a lower end configured to abut an engine block and anupper end and having a conical surface diverging radially outwardly fromthe through bore toward the upper end. The piston assemblytransportation and assembly apparatus includes a housing having a borebounded by an inner cylindrical surface extending from a first end ofthe housing toward a second end of the housing. A chamfered surfacediverges radially outwardly from the first end toward the second end andis configured to mate with the conical surface of the stuffing cone. Thesecond end has a wall extending radially inwardly from the innercylindrical surface to axially confront an upper crown of the pistonassembly.

In accordance with another aspect of the invention, a piston assemblytransportation and assembly apparatus in combination with a pistonassembly is provided. The piston assembly includes a piston head havingan upper crown with at least one piston ring groove having a piston ringdisposed therein. The piston ring is split to provide a gap between freeends of the piston ring. The piston assembly transportation and assemblyapparatus includes a housing having a bore bounded by an innercylindrical surface extending from a first end of the housing toward asecond end of the housing. The cylindrical surface is dimensioned toprevent the gap between the piston ring free ends from being completelyclosed while the piston assembly is received in the housing. A chamferedsurface diverges radially outwardly from the first end toward the secondend and the second end has a wall extending radially inwardly from theinner cylindrical surface to axially confront an upper crown of thepiston assembly.

In accordance with yet another aspect of the invention, a method oftransporting and installing a piston assembly is provided. The methodincludes providing a piston head having at least one piston ringdisposed in a ring groove with the piston ring having a free gapprovided between uncompressed opposite ends of the piston ring. Further,providing a housing having a bore bounded by an inner cylindricalsurface extending from an upper edge of a first end of the housingtoward a second end of the housing having a wall extending radiallyinwardly from the inner cylindrical surface. Further yet, disposing thepiston head in the bore of the housing with the piston head facing thesecond end of the housing without completely closing the free gap of thepiston ring. Then, transporting the piston assembly within the housing.Further, providing a stuffing cone having a through bore extendingbetween a lower end configured to abut an engine block and an upper end.Then, positioning the stuffing cone over a cylinder bore of an engineblock. Further yet, bringing the first end of the housing into abutmentwith the upper end of the stuffing cone. And, pushing the pistonassembly from the housing through the stuffing cone and into thecylinder bore.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of the presentinvention will become more readily appreciated when considered inconnection with the following detailed description of presentlypreferred embodiments and best mode, appended claims and accompanyingdrawings, in which:

FIG. 1 is a partial cross-sectional elevation view showing a pistonassembly received in a transportation and assembly apparatus constructedin accordance with one aspect of the invention with the transportationand assembly apparatus shown in a transportation state;

FIG. 2 is an enlarged partial cross-sectional elevation view of thetransportation and assembly apparatus and piston assembly shown in aninitial state of assembly;

FIG. 2A is a view similar to FIG. 2 of a transportation and assemblyapparatus constructed in accordance with another aspect of theinvention;

FIG. 2B is a view similar to FIG. 2 of a transportation and assemblyapparatus constructed in accordance with another aspect of theinvention; and

FIG. 3 is a view similar to FIG. 2 showing the piston assembly in anadvanced state of assembly.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS

Referring in more detail to the drawings, FIG. 1 illustrates a pistonassembly transportation and assembly apparatus, referred to hereafter asapparatus 10, constructed in accordance with one aspect of theinvention. The apparatus 10 provides methods of transporting andinstalling a piston assembly 12 therewith. The piston assembly 12,having a piston body, also referred to as piston head 14, and an uppercrown 16 with at least one piston ring groove, and shown here as aplurality of piston ring grooves 18, 20, 22, with respective pistonrings 24, 26, 28 disposed therein, is disposed in the apparatus 10 forstorage, transportation, and to facilitate assembly of the pistonassembly 12 within a cylinder bore 30 of an engine block 32 (FIGS. 2, 2Aand 3). The apparatus 10 provides an easy way in which to store andtransport the piston assembly 12 without damaging or otherwise impactingthe functionality of the piston rings 24, 26, 28, and also provides aneasy way in which to directly assemble the piston assembly 12 from theapparatus 10 into the cylinder bore 30.

While storing and transporting the piston assembly 12, it is importantto avoid damaging, contaminating and otherwise impacting the ability ofthe piston assembly 12 to function as intended within the cylinder bore30. One particular aspect to avoid is causing damage to the piston rings24, 26, 28. As shown in FIG. 1, the piston rings 24, 26, 28 each aresplit, thereby forming a gap 34 between free ends 36 of the piston rings24, 26, 28. The gaps 34 have a predetermined width extending between thefree ends 36 that is intended to be maintained prior to assembly and atleast in part thereafter to provide a predetermined amount of radiallyoutwardly acting expansion spring force of the rings 24, 26, 28 againstthe wall of the cylinder bore 30 during use. This spring force isdesired to allow the rings 24, 26, 28 to function as intended, whetherfunctioning primary as a compression ring 24, which seals thecompression chamber from any leakage during the combustion process; awiper ring 26, which further seals the combustion chamber and wipes thewall of the cylinder bore 30 clean of any excess oil; and/or an oil sealring 28, which also wipes excess oil from the wall of the cylinder bore30 during reciprocation of the piston head 14. As such, it is importantthat during storage and transportation of the piston assembly 10 thatthe gaps 34 be maintained, thereby avoiding unwanted radially contractedplastic deformation of the rings 24, 26, 28.

The apparatus 10 is intended to be used in combination with a standardcompression cup, also referred to as a piston ring stuffing cone, andreferred to hereafter as cone 38. The cone 38 has an annular throughbore 40 extending between a lower end 42 configured to abut a generallyflat upper sealing surface of the engine block 32 and an upper end 44.The upper end 44 has a tapered, conical surface 46 diverging radiallyoutwardly from the through bore 40 toward the upper end 44. The throughbore 40 has a lower region 48 immediately adjacent the lower end 42 thatis sized to be the same or substantially the same diameter or slightlysmaller in diameter than the cylinder bore 30 to allow the rings 24, 26,28 to be guided in an unobstructed manner into the cylinder bore 30. Thethrough bore 40 has an upper region that can be tapered in a slightconverging manner from the conical surface 46 toward the lower region48, thus causing the rings 24, 26, 28 to be slightly circumferentiallycompressed so as to slide freely into the cylinder bore 30 whileretaining their elastic spring force tending to expand an outer surfaceof the rings 24, 26, 28 into abutment with the wall of the cylinder bore30.

The apparatus 10 has a housing 52 including a bore 54 bounded by acylindrical inner surface 56 extending from a first end 58 of thehousing 52 toward a second end 60 of the housing 52. The second end 60has a wall 62 extending radially inwardly from the inner cylindricalsurface 56. The wall 62 has a through opening 64 formed therein tofacilitate disposing the piston assembly 12 into the cylinder bore 30during assembly, as discussed further below. The through opening 64 issized to accommodate a plunger 66 (FIG. 3) during assembly, such thatthe plunger 66 is free to extend through the opening 64 to push thepiston assembly 12 out of the apparatus 10, through the cone 38 and intothe cylinder bore 30. Although the wall 62 includes the opening 64, thewall 62 extends sufficiently radially inwardly from the inner surface 56to overlie an outer peripheral portion of the piston upper crown 16,thereby confronting and preventing the piston assembly 12 from passingthrough the through opening 64. The housing 52 can be constructedentirely of metal, e.g. stainless steel, plastic, or a combination ofmetal and plastic, such as shown in FIG. 2A, wherein a tubular metalportion 68, e.g. stainless steel, provides the inner surface 56, and anouter plastic portion 70 forms the wall 62 and the balance of thehousing 52.

The apparatus inner surface 56 is diametrically dimensioned to preventthe gaps 34 between the piston ring free ends 36 from being completelyclosed while the piston assembly 10 is received in the housing 52. Inaddition, the inner surface 56 is diametrically dimensioned to preventthe rings 24, 26, 28 from being dislodged or otherwise removed from thering grooves 18, 20, 22 while the piston assembly 10 is received in thehousing 52. In one construction of the housing 52, such as shown in FIG.2, the inner surface 56 provides a slight clearance fit relative to anouter surface of the rings 24, 26, 28, though the clearance does notallow the rings to be displaced sufficiently radially outwardly to beremoved from the ring grooves 18, 20, 22. In yet another construction ofa housing 152, wherein the same reference numerals offset by a factor of100 are used to identify like features, an inner surface 156 isdimensioned to have a line-to-line or slight interference fit with theouter surface of the rings 124, 126, 128, though not causing the gaps134 to be completely closed, thereby avoiding unwanted plasticdeformation of the rings 124, 126, 128, as discussed above.

The housing 52 has a chamfered surface 72 diverging radially outwardlyfrom the first end 58 toward the second end 60. The chamfered surface 72is configured having a conical taper having an angle of inclinationconfigured for flush or substantially flush abutment with the conicalsurface 46 of the cone 38. Accordingly, upon mating the respectiveconical surfaces 46, 72 with one another, a substantially continuouswall of material is formed that is substantially free of gaps, whereinthe inner surface 56 of the housing 52 is flush or substantially flushwith the upper region 50 of the cone through bore 40. It should berecognized that the inner surface 56 is no greater in diameter than theinner surface 46 of the cone 38, and can be slightly reduced indiameter, such as shown with respect to the embodiment of FIG. 2B.

In use, the piston assembly 12 is disposed at least partially in thebore 54 of the housing 52 with the upper crown 16 of the piston head 14facing the second end 60 of the housing 52 without completely closingthe free gaps 34 of the piston rings 24, 26, 28, 124, 126, 128. With thepiston assembly 12 disposed in the bore 54, the housing 52, in additionto protecting the piston assembly 12 from being damaged, acts to protectagainst the ingress of debris/contamination into the bore 54. This isfacilitated by the wall 62 overlying the piston head 14, thereby closingoff any potential path to the ingress of debris/contamination. Thepiston assembly 12 can now be stored and transported as desired forsubsequent assembly, such as in a position shown in FIG. 1.

During assembly, the stuffing cone 38 is positioned over the cylinderbore 30 in concentric relation therewith, such the lower region 48 ofthe cone 38 is flush or substantially flush with the cylinder bore 30.

Then, the first end 58 of the housing 52 is brought into nested,conforming abutment with the upper end 44 of the stuffing cone 38, suchthat the respective conical surfaces 46, 72 nest with one another toalign the bore 54 of the housing 52 axially relative to the bore 40 ofthe cone 38.

Further, the plunger 66 is then used to push the piston assembly 12axially outwardly from the housing 52 through the stuffing cone 38 andinto the cylinder bore 30. As the piston assembly 12 is urged into thecylinder bore 30, as shown in FIG. 3, the respective piston rings 24,26, 28, 124, 126, 128 are caused to compress radially inwardly by thecone 38 sufficiently to allow them to slide freely into the cylinderbore 30. Given the rings 24, 26, 28, 124, 126, 128 have remained in arelaxed or substantially relaxed and unbiased state prior to assembly,the piston rings 24, 26, 28, 124, 126, 128 retain their ability tofunction as intended within the cylinder bore 30.

Upon completing the assembly process, the housing 52 can reused asdesired. Accordingly, not only is the housing 52 well suited to storeand transport piston assemblies, but it is also economical in use.

Many modifications and variations of the present invention are possiblein light of the above teachings. It is, therefore, to be understood thatthe invention may be practiced otherwise than as specifically described,and that the scope of the invention is defined by any ultimately allowedclaims.

What is claimed is:
 1. A method of transporting and installing a pistonassembly, comprising: providing a piston head having at least one pistonring disposed in a ring groove with the piston ring having a free gapprovided between uncompressed opposite ends of the piston ring;providing a housing having a bore bounded by an inner cylindricalsurface extending from an upper edge of a first end of the housingtoward a second end of the housing having a wall extending radiallyinwardly from the inner cylindrical surface; disposing the piston headin the bore of the housing with the piston head facing the second end ofthe housing without completely closing the free gap of the piston ring;transporting the piston assembly within the housing; providing astuffing cone having a through bore extending between a lower endconfigured to abut an engine block and an upper end; positioning thestuffing cone over a cylinder bore of the engine block; bringing thefirst end of the housing into abutment with the upper end of thestuffing cone; and pushing the piston assembly from the housing throughthe stuffing cone and into the cylinder bore.
 2. The method of claim 1further including providing the first end of the housing and upper endof the stuffing ring with tapered surfaces and bringing the taperedsurfaces into conforming abutment with one another.
 3. The method ofclaim 1 further including providing a circumferential clearance fitbetween the piston ring and the inner cylindrical surface of thehousing.
 4. The method of claim 3 further including extending the pistonring into the ring groove over a circumferentially extending depth thatis greater than the circumferential clearance fit to prevent the pistonring from coming out of the ring groove while the piston assembly is inthe bore.
 5. The method of claim 1 further including reusing the housingfor subsequent storage, transportation and installation of a pistonassembly into a cylinder bore.